CN111766276A - Plant stem freezing and thawing measuring method, device, system, equipment and storage medium - Google Patents
Plant stem freezing and thawing measuring method, device, system, equipment and storage medium Download PDFInfo
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Abstract
The embodiment of the invention relates to the technical field of agricultural biological measurement, and provides a plant stem freezing and thawing measurement method, device, system, equipment and storage medium. The freeze-thaw measurement method for the plant stalks comprises the following steps: obtaining the critical dielectric constant of the plant stalks at the freezing and thawing demarcation point; acquiring a real-time impedance value of the plant stem according to a preset time interval, and converting the real-time impedance value into a real-time dielectric constant of the plant stem; and comparing the real-time dielectric constant with the critical dielectric constant to obtain the real-time freeze-thaw state of the plant stalks. The freeze-thaw measuring method for the plant stems provided by the embodiment of the invention can detect the condition that the freeze-thaw of the plant stems continuously changes along with time, measure the freeze-thaw through measuring the impedance, have accurate measuring results, and avoid damaging plant bodies without inserting a sensor into the plants.
Description
Technical Field
The embodiment of the invention relates to the technical field of agricultural biological measurement, in particular to a plant stem freezing and thawing measurement method, device, system, equipment and storage medium.
Background
Under the severe low-temperature condition in winter, plants can bear extreme freeze-thaw stress, namely, the plant stalks are gradually frozen to form a freeze-thaw event. Freeze-thaw events can lead to embolization of plant stalks, thereby affecting the transport of moisture within the plant and even leading to plant death. Therefore, the freezing and thawing condition in the plant stalks is effectively monitored, certain measures are taken to reduce embolism and damage caused by low-temperature freezing and thawing events to the maximum extent, and the method plays an important role in safe overwintering, growth and survival of the plants.
Currently, various methods have been used to detect freezing and thawing conditions inside plants, including infrared imaging, X-ray imaging, nuclear magnetic resonance imaging, ultrasound transmission, thermoeffect, diameter measurement, etc.
The infrared imaging method, the X-ray imaging method and the nuclear magnetic resonance imaging method need special instruments, and although the propagation of ice in the stem can be observed visually, the infrared imaging method, the X-ray imaging method and the nuclear magnetic resonance imaging method are only used for laboratory experiments and are difficult to measure in real time in an outdoor environment; the ultrasonic emission method is based on the principle that the changes of elasticity and density in plant stalks can affect the propagation speed of sound waves in the freezing and thawing process, can be used for nondestructive detection and can be used under field conditions, but the sound wave speed is easily influenced by the wood structure in the stalks, so that the anti-interference performance is poor; the heat effect method is based on the principle that plant stems exchange heat in the freezing and thawing process, release heat in the freezing process and absorb heat in the thawing process, and is simple and convenient, easy for field measurement, but a sensor needs to be inserted into the plant and has destructiveness, and in the freezing and thawing process, the heat is dispersed quickly and is difficult to quantitatively and accurately detect; the diameter measurement method is based on that the diameter of plant stalks changes in the freezing and thawing process, the freezing and thawing changes are measured in an indirect diameter detection mode, the diameter measurement can achieve the effect of nondestructive detection, but most researches show that the diameter changes are mainly caused by the change of external phloem, so that the diameter changes are difficult to truly reflect the freezing and thawing condition of internal xylem.
Disclosure of Invention
The embodiment of the invention provides a plant stem freezing and thawing measurement method, device, system, equipment and storage medium, which are used for solving the problems that the conventional plant stem freezing and thawing measurement technology is low in accuracy and destructive to plants.
In a first aspect, an embodiment of the present invention provides a method for measuring freeze thawing of plant stalks, including:
obtaining the critical dielectric constant of the plant stalks at the freezing and thawing demarcation point;
acquiring a real-time impedance value of the plant stem according to a preset time interval, and converting the real-time impedance value into a real-time dielectric constant of the plant stem;
and comparing the real-time dielectric constant with the critical dielectric constant to obtain the real-time freeze-thaw state of the plant stalks.
Further, the obtaining of the real-time impedance value of the plant stem according to the preset time interval specifically includes:
transmitting an excitation signal to the plant stem at a preset time interval, and receiving a response signal of the excitation signal;
and calculating the impedance value by utilizing Fourier transform according to the excitation signal and the response signal.
Further, sequentially transmitting the excitation signal to a plurality of different measurement points of the plant stalk according to a preset time interval, and receiving the response signals of the plurality of different measurement points;
and calculating real-time impedance values of the different measuring points by utilizing Fourier transform according to the excitation signals and the response signals of the different measuring points.
Furthermore, the plurality of different measuring points are distributed on the periphery of the plant stem and are positioned in the same plane;
obtaining two-dimensional distribution of real-time impedance values in the plane by using a finite element model differential imaging method according to the real-time impedance values of the different measurement points;
converting the two-dimensional distribution of real-time impedance values into a two-dimensional distribution of the real-time dielectric constant.
Further, the comparing the real-time dielectric constant with the critical dielectric constant to obtain the freeze-thaw state of the plant stalks specifically comprises:
when the real-time dielectric constant is smaller than the critical dielectric constant, judging that the plant stalk is in a frozen state;
and when the real-time dielectric constant is larger than the critical dielectric constant, judging that the plant stalk is in a non-frozen state.
In a second aspect, an embodiment of the present invention provides a plant stem freezing and thawing measuring device, including:
the first acquisition unit is used for acquiring the critical dielectric constant of the plant stalks at a freezing-thawing dividing point;
the second acquisition unit is used for acquiring the real-time impedance value of the plant stem according to a preset time interval and converting the real-time impedance value into the real-time dielectric constant of the plant stem;
and the comparison unit is used for comparing the real-time dielectric constant with the critical dielectric constant to obtain the real-time freeze-thaw state of the plant stalks.
In a third aspect, the freeze-thaw measuring system for plant stalks provided in the embodiment of the present invention further includes:
the impedance measurement chip is used for generating an excitation signal and calculating a real-time impedance value of the plant stem according to a response signal of the excitation signal;
the microcontroller is in communication connection with the impedance measuring chip and is used for controlling the impedance measuring chip to generate an excitation signal according to a preset time interval;
the transmitting probe and the receiving probe are respectively in communication connection with the impedance measuring chip, the transmitting probe is used for sending the excitation signal to the plant stem, and the receiving probe is used for receiving a response signal of the excitation signal;
and the data processor is in communication connection with the impedance measurement chip and is used for executing the plant stem freezing and thawing measurement method in the first aspect.
Further, the plant stem freezing and thawing measuring system further comprises:
the impedance measurement chip is in communication connection with the transmitting probe and the receiving probe through the analog multiplexer;
the microcontroller is also in communication connection with the analog multiplexer and is used for controlling the analog multiplexer to switch signal channels.
In a fourth aspect, an embodiment of the present invention provides an electronic device, including: a memory, a processor and a computer program stored on the memory and operable on the processor, the processor when executing the program implementing the plant stem freezing and thawing measurement method of the first aspect.
In a fifth aspect, an embodiment of the present invention provides a non-transitory computer-readable storage medium, on which a computer program is stored, and the computer program, when executed by a processor, implements the plant stem freezing and thawing measurement method of the first aspect.
The freeze-thaw measurement method for the plant stalks provided by the embodiment of the invention obtains the dielectric constant of the plant stalks to be measured by acquiring the impedance value of the plant stalks to be measured in real time, and obtains the real-time freeze-thaw condition of the plant stalks to be measured by comparing the real-time dielectric constant with the critical dielectric constant at the freeze-thaw demarcation point. The condition that the freeze thawing of the plant stems continuously changes along with time can be detected; compared with the traditional heat effect method, the sensor does not need to be inserted into the plant, so that the damage to the plant body is avoided; in the freezing and thawing process of the plant stalks, the change of the dielectric constant is caused by the change of ice water in the plant stalks, and the impedance is a function of the dielectric constant, so that the freezing and thawing of the plant stalks can be accurately measured through the measurement of the impedance.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a schematic flow chart of a freeze-thaw measurement method for plant stems according to an embodiment of the invention;
FIG. 2 is a schematic structural diagram of a plant stem freezing and thawing measuring device according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a plant stem freezing and thawing measurement system according to an embodiment of the present invention;
fig. 4 is a schematic physical structure diagram of an electronic device according to an embodiment of the invention.
In the figure: 1. measuring a plate; 11. an impedance measurement chip; 12. a microcontroller; 2. a transmitting probe; 3. receiving a probe; 4. a data processor; 5. an analog multiplexer; 6. a coaxial line.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a schematic flow chart of a freeze-thaw measurement method for plant stems according to an embodiment of the present invention, and as shown in fig. 1, the freeze-thaw measurement method for plant stems includes:
and S100, obtaining the critical dielectric constant of the plant stalks at the freezing-thawing dividing point.
Specifically, the plant stalks to be detected are frozen under the condition of a freezing experiment, the dielectric constant value is detected in real time, the freezing condition of the plant stalks to be detected is observed from the cross section, the first dielectric constant and the second dielectric constant which are completely frozen when the plant stalks begin to freeze are recorded, and the critical dielectric constant value is a data interval from the first dielectric constant to the second dielectric constant.
And S200, acquiring a real-time impedance value of the plant stem according to a preset time interval, and converting the real-time impedance value into a real-time dielectric constant of the plant stem according to the real-time impedance value.
Specifically, the dielectric constant is mainly related to the capacitive reactance, namely the imaginary part of the impedance, and after the real-time impedance value of the plant stem to be detected is obtained, the real-time dielectric constant of the plant stem to be detected can be obtained according to the relationship between the capacitive reactance and the capacitance value and the relationship between the capacitance value and the dielectric constant.
For example, the real-time impedance value of the plant stalks is measured by two electrode plates to obtain the imaginary part of the impedance, under a specific frequency, the capacitance value is calculated according to the formula c ═ 1/(2 pi fI), and then the dielectric constant is calculated according to the formula c ═ 4 pi kdc/s, wherein c is the capacitance value, f is the frequency, I is the imaginary part of the impedance and is the dielectric constant, k is the electrostatic constant, d is the distance between the capacitor plates, and s is the facing area of the capacitor plates.
And S300, comparing the real-time dielectric constant with the critical dielectric constant to obtain the real-time freeze-thaw state of the plant stalks.
Specifically, when the dielectric constant is smaller than the critical dielectric constant, namely the real-time dielectric constant is smaller than the first dielectric constant, the plant stalk is judged to be in a frozen state; and when the dielectric constant is larger than the critical dielectric constant, namely the real-time dielectric constant is larger than the second dielectric constant, judging that the plant stalk is in a non-frozen state. Because the compared dielectric constant is the real-time dielectric constant of the preset time interval, the condition that the freeze thawing of the plant stalks changes along with the time is finally obtained.
The freeze-thaw measurement method for the plant stalks provided by the embodiment of the invention obtains the dielectric constant of the plant stalks to be measured by acquiring the impedance value of the plant stalks to be measured in real time, and obtains the real-time freeze-thaw condition of the plant stalks to be measured by comparing the real-time dielectric constant with the critical dielectric constant at the freeze-thaw demarcation point. The real-time measurement of the freeze thawing of the plant stems is realized, and the condition that the freeze thawing of the plant stems continuously changes along with time can be detected; compared with the traditional heat effect method, the sensor does not need to be inserted into the plant, so that the damage to the plant body is avoided; in the freezing and thawing process of the plant stalks, the change of the dielectric constant is caused by the change of ice water in the plant stalks, and the impedance is a function of the dielectric constant, so that the freezing and thawing of the plant stalks can be accurately measured through the measurement of the impedance.
On the basis of the above embodiment, the step S200 of obtaining the real-time impedance value of the plant stem at the preset time interval specifically includes the steps of:
and transmitting an excitation signal to the plant stem at preset time intervals, and receiving a response signal of the excitation signal.
And calculating the impedance value by utilizing Fourier transform according to the excitation signal and the response signal.
Specifically, an excitation signal, such as a sine wave voltage signal with a specific frequency, is emitted to the plant stalk to be tested at a preset time interval, and the sine wave voltage signal with the specific frequency is used for exciting an external complex impedance to obtain a response signal of the complex impedance of the plant stalk to be tested. Performing analog-to-digital conversion on the response signal, sampling the digital signal, performing Fourier transform (DFT), and performing DFT operation to obtain a real value and an imaginary value, as follows:
wherein, x (f) is the energy of the signal at the frequency point; x (n) is the output after analog-to-digital conversion; cos (n) and sin (n) are the sampling test vectors for frequency bins; r and I represent the real and imaginary values, respectively, and m is the number of samples. By using R and I obtained by DFT treatment, namely obtaining
Then the impedance magnitude is 1/(DFT magnitude × gain factor) and the impedance phase is tan-1(I/R). Due to the effect of amplification, a coefficient correction needs to be performed with an element of known fixed impedance value before measurement to calibrate the gain coefficient.
It should be noted that the excitation signal in the embodiment of the present invention may be a set of sine wave voltage signals with fixed frequency, or may be a plurality of sets of sine wave signals with different frequencies. For example, two groups of sine wave signals with different frequencies are transmitted to the plant stalks in a frequency sweeping mode, difference frequency imaging is carried out on data measured under two groups of excitation signals with different frequencies, namely, interpolation of the measured data under two groups of different frequencies is utilized to reconstruct relative change of impedance distribution, so that the influence of a xylem structure in the stalks on a measurement result can be reduced, the anti-interference performance is strong, and the method can be used for freeze-thaw measurement of the plant stalks with unobvious transient impedance change, namely freeze-thaw measurement of the plant stalks with slower freezing speed.
In the embodiment of the invention, the impedance value of one measuring point of the plant stem can be obtained; the impedance values of a plurality of different measuring points of the plant stem can also be obtained, specifically, excitation signals are sequentially transmitted to the plurality of different measuring points of the plant stem according to a preset time interval, and response signals of the excitation signals of the plurality of different measuring points are received; and calculating real-time impedance values of the different measuring points by utilizing Fourier transform according to the excitation signals and the response signals of the different measuring points.
When the impedance value of only one measuring point of the plant stem is obtained, the freezing and thawing condition of the whole plant stem is obtained; when obtaining the impedance values of a plurality of different measurement points of the plant stalks, the freezing and thawing condition of the plant stalks of the plurality of measurement points is obtained. For example, by measuring the impedance values at a plurality of points along the length of the plant stalks, freezing and thawing conditions of a plurality of sections along the length of the plant stalks can be obtained; or measuring the impedance values of a plurality of position points along the circumferential direction of the plant stem, the freeze-thaw conditions of a plurality of regions along the circumferential direction of the plant stem can be obtained.
In order to obtain the freeze-thawing condition of the plant stalks at different depths, in the embodiment of the invention, the plurality of different measuring points are distributed on the periphery of the plant stalks and are positioned in the same plane;
obtaining two-dimensional distribution of real-time impedance values in the plane by using a finite element model differential imaging method according to the real-time impedance values of the different measurement points;
converting the two-dimensional distribution of real-time impedance values into a two-dimensional distribution of the real-time dielectric constant.
Specifically, after the real-time impedance values of different measuring points in the same plane of the periphery of the plant stem are obtained, in the plane, the two-dimensional distribution of the impedance values of the plant stem on the plane is obtained by utilizing the differential imaging calculation of the finite element model. The two-dimensional distribution of real-time impedance values is then converted into a two-dimensional distribution of real-time dielectric constants according to the equations c 1/(2 pi fI) and 4 pi kdc/s, where d is the distance between each element in the finite element model and s is the area between each element in the finite element model. And then comparing the actually measured real-time dielectric constant with the critical dielectric constant based on the two-dimensional distribution of the dielectric constant, namely comparing the dielectric constant of each unit in the finite element model with the critical dielectric constant, wherein the unit with the dielectric constant smaller than the critical dielectric constant is in a frozen state, and the unit with the dielectric constant larger than the critical dielectric constant is in a non-frozen state, so that the freeze-thaw two-dimensional distribution in the plane is obtained.
It should be noted that, in the embodiment of the present invention, after the real-time impedance values of a plurality of different measurement points in the same plane at the periphery of the plant stem are obtained, the real-time impedance values of the plurality of different measurement points are first converted into the dielectric constant, then based on the dielectric constant values of the plurality of different measurement points, the two-dimensional distribution of the dielectric constant of the plant stem on the plane is obtained by using the finite element model differential imaging calculation in the plane, and then the two-dimensional distribution of the dielectric constant is obtained to obtain the freeze-thaw two-dimensional distribution.
The plant stem freeze-thaw measuring method provided by the embodiment of the invention obtains the two-dimensional distribution of the real-time dielectric constant through measuring the real-time impedance values of a plurality of measuring points on the same plane at the periphery of the plant stem and a finite element model differential imaging method, thereby obtaining the two-dimensional distribution of the real-time freeze-thaw state of the plant stem in a certain plane.
When the plant stalks are frozen, the plant stalks are frozen from outside to inside, and when the plant stalks are melted, the plant stalks are melted from outside to inside. The two-dimensional distribution of the real-time freeze-thaw state obtained by the method for measuring the freeze-thaw of the plant stems provided by the embodiment of the invention can clearly display the real-time freeze-thaw condition of the plant stems in the depth direction from outside to inside, can know the freeze depth of the plant stems at different moments, and more accurately display the freeze-thaw condition of the plant stems continuously changing along with time on a certain plane. For example, the plane where the plurality of measuring points are located is perpendicular to the plant stalks, the situation that the freeze-thaw two-dimensional distribution of the plant stalks on the cross section is continuously changed along with time is obtained.
Fig. 2 is a schematic structural view of a plant stem freezing and thawing measuring device according to an embodiment of the present invention, and as shown in fig. 2, the plant stem freezing and thawing measuring device includes:
the first acquisition unit 201 is used for acquiring the critical dielectric constant of the plant stalks at a freezing-thawing dividing point;
a second obtaining unit 202, configured to obtain a real-time impedance value of the plant stalk according to a preset time interval, and convert the real-time impedance value into a real-time dielectric constant of the plant stalk;
and the comparison unit 203 is used for comparing the real-time dielectric constant with the critical dielectric constant to obtain the real-time freeze-thaw state of the plant stalks.
Specifically, when the real-time dielectric constant is smaller than the critical dielectric constant, the plant stalks are judged to be in a frozen state; when the real-time dielectric constant is larger than the critical dielectric constant, the plant stalks are judged to be in the non-frozen state
Fig. 3 is a schematic structural view of a plant stem freezing and thawing measuring system according to an embodiment of the present invention, and as shown in fig. 3, the plant stem freezing and thawing measuring system includes:
the impedance measurement chip 11 is used for generating an excitation signal and calculating a real-time impedance value of the plant stem according to a response signal of the excitation signal;
the microcontroller 12 is in communication connection with the impedance measuring chip 11, and is used for controlling the impedance measuring chip 11 to generate an excitation signal at preset time intervals;
the device comprises a transmitting probe 2 and a receiving probe 3, wherein the transmitting probe 2 and the receiving probe 3 are respectively in communication connection with the impedance measuring chip 11, the transmitting probe 2 is used for sending the excitation signal to the plant stalks, and the receiving probe 3 is used for receiving the response signal of the excitation signal.
And the data processor 4 is in communication connection with the impedance measurement chip 11, and is used for executing the plant stem freezing and thawing measurement method of the embodiment.
Specifically, in the embodiment of the present invention, the impedance measurement chip 11 is based on a vector voltage-current method, and applies a test voltage signal to the plant stem, measures a signal current flowing through the plant stem, and calculates the impedance of the plant stem from the ratio of the voltage and the current. The embodiment of the invention adopts AD5933, and the AD5933 is a high-precision impedance digital direct conversion system and comprises a frequency generator and an on-chip analog-digital converter. The frequency generator generates a voltage signal with a specific frequency to excite an external complex impedance, and a response signal of the complex impedance is obtained. For each frequency point, the AD5933 calculates a DFT, and the multiplication and accumulation corresponding to 1024 samples of each frequency point are as follows:
the impedance amplitude is:
the impedance phase is:
impedance phase tan-1(I/R) -system phase
Wherein, due to the influence of amplification factor, a coefficient correction is needed to be carried out by using an element with a known fixed impedance value before measurement so as to calibrate the gain coefficient. The system phase needs to be measured between the input and output of the signal with pure resistance.
The AD5933 utilizes the direct digital frequency synthesizer technology to enable the frequency resolution to be less than 0.1Hz, utilizes an additional circuit to measure the impedance within the range of 100 omega to 10M omega at most, and has the characteristics of high precision and wide range, and the system precision is within 0.5 percent. And the influence of system and loop impedance can be eliminated by short circuit correction before measurement, and the measurement accuracy is greatly improved.
The microcontroller 12 of the embodiment of the invention is an STM32F103 series chip, and communicates with the AD5933 chip through an I2C bus, and the microcontroller 12 sends corresponding signals to control the AD5933 chip to transmit sine wave excitation signals with corresponding frequency and amplitude.
The transmitting probe 2 and the receiving probe 3 are both the same metal electrodes, and a square copper sheet electrode is adopted in the embodiment of the invention. When in measurement, the transmitting probe 2 and the receiving probe 3 are attached to the surface of the plant stalk. The microcontroller 12 controls the impedance measuring chip to generate an excitation signal, the excitation signal is transmitted to the plant stem through the transmitting probe 2, and the response signal is received by the receiving probe 3. When the impedance measurement needs to be carried out on a plurality of measurement points of the plant stalks, a plurality of pairs of transmitting probes 2 and receiving probes 3 are oppositely attached to the periphery of the plant stalks and are uniformly distributed in an annular shape, and the freeze-thaw two-dimensional distribution on the plane, namely the freeze-thaw two-dimensional distribution on the cross section of the plant stalks, is measured on the same plane.
The data processor 4 is connected with the impedance measuring chip 11 in a wired or wireless way. Specifically, the communication mode may be USB serial communication or bluetooth serial communication. In the embodiment of the invention, the data processor 4 is positioned on an upper computer, and the upper computer is programmed by MATLAB to realize specific functions of the upper computer, including data storage, data correction, model calculation and differential imaging. The impedance measuring chip 11 sends the calculated impedance value to the data processor 4 of the upper computer, the data processor 4 firstly converts the measured real-time impedance value into a real-time dielectric constant, and then the real-time freeze-thaw state of the plant stalks is obtained through the real-time dielectric constant. For a specific calculation method, reference is made to the above embodiments, which are not described herein again. The freeze-thaw measuring system for the plant stems provided by the embodiment of the invention can obtain the continuous change condition of the whole freeze-thaw state of the plant stems along with time by measuring the impedance values of the plant stems at different times.
The freeze-thaw measuring system for the plant stems provided by the embodiment of the invention can also obtain the continuous change condition of the freeze-thaw state of the plurality of measuring points of the plant stems along with time by measuring the impedance values of the plurality of measuring points of the plant stems at different times. When the plant stalk impedance values of a plurality of different measuring points need to be measured, a plurality of pairs of transmitting probes and receiving probes are needed. When a plurality of pairs of transmitting probes and receiving probes are arranged along the length direction of the plant stalks, the freeze-thaw states of different areas in the length direction of the plant stalks can be obtained; when a plurality of pairs of transmitting probes and receiving probes are arranged along the circumferential direction of the plant stalks and are positioned in the same plane, the freeze-thaw states of different areas of the plant stalks in the circumferential direction can be obtained.
If the finite element model differential imaging processing is carried out on a plurality of measured impedance values positioned on the circumferential direction of the plant stem, the two-dimensional distribution condition of the freeze-thaw state on the cross section of the plant stem can be obtained. By carrying out differential imaging on the plant stem impedance of a plurality of different measuring points at a plurality of moments in a period of time, the stem freezing-thawing two-dimensional distribution condition of the plant stems on the cross section, which continuously changes along with the time, can be obtained.
The plant stem freezing and thawing measurement system provided by the embodiment of the invention further comprises:
the analog multiplexer 5, the impedance measurement chip 11 is connected with the transmitting probe 2 and the receiving probe 3 through the analog multiplexer 5;
the microcontroller 12 is also communicatively connected to the analog multiplexer 5, and is configured to control the analog multiplexer 5 to switch signal channels.
Specifically, the analog multiplexer 5 and the impedance measuring chip 11, and the analog multiplexer 5 and the transmitting probe 2 and the receiving probe 3 are in communication connection through the coaxial line 6, so that signal transmission is hardly interfered by external signals, and reliability and accuracy of signal transmission are guaranteed. The channel signal bandwidth of the analog multiplexer 5 completely covers the frequency range of the impedance measuring chip 11.
In the embodiment of the present invention, the analog multiplexer 5 is based on the analog multiplexer chip ADG 1209. The ADG1209 chip has two one-to-four analog channels, and can connect up to four pairs of transmitting and receiving probes. Only a corresponding pair of channels in the ADG1209 chip are gated during the same time period. The channel signal bandwidth of the ADG1209 chip can reach 630MHz, and the measurement frequency of the impedance measurement chip AD5933 can be completely covered.
In the embodiment of the present invention, the microcontroller 12 is further configured to determine whether all channels of the analog multiplexer 5 have been measured, and if all the channels have been measured, control the data processor 4 to perform data processing on the impedance value, so as to obtain freeze thawing of the plant stalks; if the channels are not completely measured, the impedance measuring chip 11 is controlled to continue generating the excitation signal.
The analog multiplexer 5 may also use other high performance analog multiplexing chips similar to the ADG1209, such as the ADG1208 chip, which has a pair of eight analog channels, and the two ADGs 1208 can form two pair of eight analog channels, and can simultaneously receive at most eight pairs of transmitting probes and receiving probes, thereby realizing the measurement of impedance in a wider range. Certainly, if impedance values of more measurement points of the plant stalks are required to be measured, more analog multiplexer 5 can be adopted according to actual needs to obtain more measurement points.
In the freeze-thaw measuring system for plant stalks provided by the embodiment of the present invention, the impedance measuring chip 11 and the microcontroller 12 may be simultaneously located on one measuring board 1, the measuring board 1 includes a data interface module, the data interface module includes a first interface module and a second interface module, the first interface module is connected to the impedance measuring chip 11 and the analog multiplexer 5, and the second interface module is connected to the impedance measuring chip 11 and the data processor 4. The second interface module is used for the impedance measurement chip 11 to send an impedance value to the data processor 4, such as UART serial port communication. The first interface module comprises an analog signal connection module and a digital signal connection module, and is two IO signal interfaces. The microcontroller 12 controls the analog multiplexer 5 to switch channels through the digital signal connection module; the impedance measurement chip 11 sends a sine wave excitation signal to the analog multiplexer 5 through the analog signal connection module, the sine wave excitation signal is sent to the end of the transmitting probe 2 through the analog multiplexer 5, and then a response signal received by the receiving probe 3 is returned to the impedance measurement chip 11 through the analog signal connection module through the analog multiplexer 5, so that the impedance measurement chip 11 can calculate an impedance value.
Fig. 4 is a schematic structural diagram of an electronic device according to an embodiment of the present invention, which includes a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the program, the steps of the method for freeze-thaw measurement of plant stalks according to the embodiment are implemented.
Fig. 4 illustrates a physical structure diagram of an electronic device, which may include, as shown in fig. 4: a processor (processor)410, a communication Interface 420, a memory (memory)430 and a communication bus 440, wherein the processor 410, the communication Interface 420 and the memory 430 are communicated with each other via the communication bus 440. The processor 410 may call logic instructions in the memory 430 to perform the following method: obtaining the critical dielectric constant of the plant stalks at the freezing and thawing demarcation point; acquiring a real-time impedance value of the plant stem according to a preset time interval, and converting the real-time impedance value into a real-time dielectric constant of the plant stem; and comparing the real-time dielectric constant with the critical dielectric constant to obtain the real-time freeze-thaw state of the plant stalks.
In addition, the logic instructions in the memory 430 may be implemented in the form of software functional units and stored in a computer readable storage medium when the software functional units are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
Embodiments of the present invention also provide a non-transitory computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the method for freeze-thaw measurement of plant stalks provided in the above embodiments is provided.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A plant stem freeze-thaw measurement method is characterized by comprising the following steps:
obtaining the critical dielectric constant of the plant stalks at the freezing and thawing demarcation point;
acquiring a real-time impedance value of the plant stem according to a preset time interval, and converting the real-time impedance value into a real-time dielectric constant of the plant stem;
and comparing the real-time dielectric constant with the critical dielectric constant to obtain the real-time freeze-thaw state of the plant stalks.
2. The freeze-thaw measurement method for plant stalks according to claim 1, wherein the obtaining of the real-time impedance value of the plant stalks at a preset time interval specifically comprises:
transmitting an excitation signal to the plant stem at a preset time interval, and receiving a response signal of the excitation signal;
and calculating the impedance value by utilizing Fourier transform according to the excitation signal and the response signal.
3. The method for freeze-thaw measurement of plant stalks according to claim 2,
sequentially transmitting the excitation signal to a plurality of different measurement points of the plant stem at preset time intervals, and receiving the response signals of the plurality of different measurement points;
and calculating real-time impedance values of the different measuring points by utilizing Fourier transform according to the excitation signals and the response signals of the different measuring points.
4. The plant stem freeze-thaw measurement method according to claim 3,
the plurality of different measuring points are distributed on the periphery of the plant stem and are positioned in the same plane;
obtaining two-dimensional distribution of real-time impedance values in the plane by using a finite element model differential imaging method according to the real-time impedance values of the different measurement points;
converting the two-dimensional distribution of real-time impedance values into a two-dimensional distribution of the real-time dielectric constant.
5. The method for freeze-thaw measurement of plant stalks according to any one of claims 1 to 4, wherein the comparing the real-time permittivity with the critical permittivity to obtain the freeze-thaw state of the plant stalks comprises:
when the real-time dielectric constant is smaller than the critical dielectric constant, judging that the plant stalk is in a frozen state;
and when the real-time dielectric constant is larger than the critical dielectric constant, judging that the plant stalk is in a non-frozen state.
6. A plant stem freezing and thawing measuring device is characterized by comprising:
the first acquisition unit is used for acquiring the critical dielectric constant of the plant stalks at a freezing-thawing dividing point;
the second acquisition unit is used for acquiring the real-time impedance value of the plant stem according to a preset time interval and converting the real-time impedance value into the real-time dielectric constant of the plant stem;
and the comparison unit is used for comparing the real-time dielectric constant with the critical dielectric constant to obtain the real-time freeze-thaw state of the plant stalks.
7. A plant stem freezing and thawing measurement system is characterized by comprising:
the impedance measurement chip is used for generating an excitation signal and calculating a real-time impedance value of the plant stem according to a response signal of the excitation signal;
the microcontroller is in communication connection with the impedance measuring chip and is used for controlling the impedance measuring chip to generate an excitation signal according to a preset time interval;
the transmitting probe and the receiving probe are respectively in communication connection with the impedance measuring chip, the transmitting probe is used for sending the excitation signal to the plant stem, and the receiving probe is used for receiving a response signal of the excitation signal;
a data processor, communicatively connected to the impedance measurement chip, for performing the plant stem freezing and thawing measurement method of any one of claims 1 to 5.
8. The plant stem freeze-thaw measuring system according to claim 7, further comprising:
the impedance measurement chip is in communication connection with the transmitting probe and the receiving probe through the analog multiplexer;
the microcontroller is also in communication connection with the analog multiplexer and is used for controlling the analog multiplexer to switch signal channels.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor when executing the program implements the plant stem freeze-thaw measuring method according to any one of claims 1 to 5.
10. A non-transitory computer readable storage medium having stored thereon a computer program, wherein the computer program when executed by a processor implements the method of freeze-thaw measurement of plant stalks of any one of claims 1 to 5.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113418963A (en) * | 2021-06-22 | 2021-09-21 | 北京工商大学 | Trunk freezing-thawing impedance image real-time detection method and system |
| CN116294415A (en) * | 2023-04-06 | 2023-06-23 | 珠海格力电器股份有限公司 | Refrigerator control method and device and refrigerator |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1875883A (en) * | 2006-06-08 | 2006-12-13 | 天津大学 | Mixing bio-impedance measurement method based on Fourier conversion |
| CN101871974A (en) * | 2010-06-18 | 2010-10-27 | 华南理工大学 | Impedance spectroscopy measurement method |
| CN102599908A (en) * | 2012-04-09 | 2012-07-25 | 成都晨德科技有限公司 | Electrical impedance tomography method based on gridding displacement model with balance factor |
| CN102688041A (en) * | 2012-06-08 | 2012-09-26 | 思澜科技（成都）有限公司 | Three-dimensional electrical impedance tomography method based on crisscross-arranged electrodes |
| CN103018284A (en) * | 2012-12-14 | 2013-04-03 | 北京航空航天大学 | Four-terminal electrical impedance tomography method based on two-terminal impedance measurement mode |
| CN104155346A (en) * | 2014-08-18 | 2014-11-19 | 江苏大学 | Method for testing critical freeze damage temperature of plant, and system thereof |
| CN104977321A (en) * | 2015-07-14 | 2015-10-14 | 中国矿业大学 | Method for measuring freeze-thaw damage gradient and anisotropy |
| CN105241377A (en) * | 2015-09-16 | 2016-01-13 | 中国农业大学 | Plant three-dimensional measurement method and system based on PTZ camera system parameters and video frames |
| CN110174698A (en) * | 2019-06-27 | 2019-08-27 | 中国石油大学(华东) | A kind of elastic impedance inversion method and system based on orientation Fourier coefficient |
| CN111007087A (en) * | 2019-11-12 | 2020-04-14 | 北京林业大学 | Nondestructive testing sensor, system and method for freeze-thaw characteristics of standing trees |
-
2020
- 2020-06-16 CN CN202010548154.XA patent/CN111766276A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1875883A (en) * | 2006-06-08 | 2006-12-13 | 天津大学 | Mixing bio-impedance measurement method based on Fourier conversion |
| CN101871974A (en) * | 2010-06-18 | 2010-10-27 | 华南理工大学 | Impedance spectroscopy measurement method |
| CN102599908A (en) * | 2012-04-09 | 2012-07-25 | 成都晨德科技有限公司 | Electrical impedance tomography method based on gridding displacement model with balance factor |
| CN102688041A (en) * | 2012-06-08 | 2012-09-26 | 思澜科技（成都）有限公司 | Three-dimensional electrical impedance tomography method based on crisscross-arranged electrodes |
| CN103018284A (en) * | 2012-12-14 | 2013-04-03 | 北京航空航天大学 | Four-terminal electrical impedance tomography method based on two-terminal impedance measurement mode |
| CN104155346A (en) * | 2014-08-18 | 2014-11-19 | 江苏大学 | Method for testing critical freeze damage temperature of plant, and system thereof |
| CN104977321A (en) * | 2015-07-14 | 2015-10-14 | 中国矿业大学 | Method for measuring freeze-thaw damage gradient and anisotropy |
| CN105241377A (en) * | 2015-09-16 | 2016-01-13 | 中国农业大学 | Plant three-dimensional measurement method and system based on PTZ camera system parameters and video frames |
| CN110174698A (en) * | 2019-06-27 | 2019-08-27 | 中国石油大学(华东) | A kind of elastic impedance inversion method and system based on orientation Fourier coefficient |
| CN111007087A (en) * | 2019-11-12 | 2020-04-14 | 北京林业大学 | Nondestructive testing sensor, system and method for freeze-thaw characteristics of standing trees |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113418963A (en) * | 2021-06-22 | 2021-09-21 | 北京工商大学 | Trunk freezing-thawing impedance image real-time detection method and system |
| CN113418963B (en) * | 2021-06-22 | 2022-08-16 | 北京工商大学 | Trunk freezing-thawing impedance image real-time detection method and system |
| CN116294415A (en) * | 2023-04-06 | 2023-06-23 | 珠海格力电器股份有限公司 | Refrigerator control method and device and refrigerator |
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